Movement into & out of cell + Biological molecules Flashcards
Define osmosis
Go from high water potential to low water potential gradient through a partially permeable membrane
Where does the energy for diffusion come from
kinetic energy of random movement of
molecules and ions
What does equilibrium mean in the case of diffusion?
When particles are evenly distributed through a space, we say equilibrium, particles still move but no net movement in specific directions
Why is diffusion important? [3]
1) Getting nutrients into the blood
2) Gas exchange for respiration
3) Absorbing carbon dioxide into leaf
4 factors to speed up/down diffusion [4]
1) Concentration gradient- the bigger the gradient the faster it is
2) Temperature, more energy at higher heat
3) Surface area
4) Distance - the larger the distance, the longer time to diffuse
Plasma membrane
Semi-permeable/organelles are semi-permeable
define diffusion
from high concentration to low concentration gradient and requires no energy
Water potential
Potential energy in water
ψ
Turgor pressure [2]
1) pressure within cells that pushes against the cell
2) more water in cell = high turgor pressure
Hypertonic solution[2]
higher solute concentration outside the cell, plasmolysis
Hypotonic solution [2]
Lower concentration outside the cell, turgid
cell being plasmolysis [3]
1) plant cell is placed in a hypertonic solution
2) net movement of water out of the cell
3) causing a reduction in turgor pressure and the cell membrane to peel back from the cell wall.
effect of isotonic
No net movement of water, cell is the same
Why is active transport used in plant cells [2]
1) Plant need ions
2) Ions are lower concentration in the soil than they are in the root hair cells, plant is forced to use active transport to get enough ions
Describe how Ions move into guard cells [3]
1) Ions move against the concentration gradient
2) Through proteins in the cell membrane
3) uses energy from respiration
Two environmental factors that cause plants to wilt [2]
Lack of water; [1 mark]
High temperature; [1 mark]
Low humidity / dry air; [1 mark]
Wind; [1 mark]
Explain why Plant roots cannot absorb these mineral ions by diffusion [2]
Diffusion is the movement of a substance down a concentration gradient [1 mark]
To be taken up by the root the ions must be moved against the concentration gradient [1 mark]
Define active transport
the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration.
How is active transport done [3]
1) Protein carriers are required for active transport
2) Has a specific shape to only transport certain molecules
3) Requires energy
Why do plants need active transport
Soil has a low mineral ion concentration compared to root hair cell
Give 1 similiarity and 1 difference between osmosis & active transport
1) Osmosis does down a concentration gradient, active transport is against a concentration gradient
2) Both go through a semi-permeable membrane
Give 1 similiarity and 1 difference between diffusion and osmosis
1) Both go down the concentration gradient
2) Diffusion doesn’t need to go through a semi-permeable cell membrane
Give 1 similiarity and 1 difference between diffusion and active transport
1) Diffusion goes down concentration. active transport is against the concentration gradient
2) Both involve movement of particles
Do the following process use metabolic energy:
1) Uptake of water by roots
2) C02 moving out of blood into the lungs
3) Uptake of ions by roots
4) Change in turgor pressure in plant cells
1) No
2) No
3) Yes
4) No
Which feature of a cell membrane allows active transport
Protein carrier
How would increasing surface area affect rate of diffusion
Big= fast
small= slow
After chemical digestion, what is
1) protein
2) carbohydrates
3) Lipids
broken down into?
1) Amino acid
2) Glucose
3) Glycerol and 3 fatty acid
What 3 chemical elements make up of the majority of biological molecules
1) Carbon
2) Hydrogen
3) Oxygen
Function of
1) starch,
2) glycerol,
3) cellulose
1) Plant use to store energy
2) Animals use to store energy in liver
3) Plant used to make cell walls
Solute
Substance that can be dissolved in solvent
Solution
Combination of solvent and solute
What is iodine used for? Positive results?
Starch
Turns into blue/black
What is biuret used for? Positive results?
Protein
Blue to purple
What is benedict’s solution used for? Positive results?
Reducing Sugar
Red- orange- yellow
What is ethanol used for? Positive results?
Fat
Cloudy
What is DCPIP used for?
Positive results?
VItamin C
Yellow
What elements are fat made of
carbon, oxygen, and hydrogen
What elements are protein made of
carbon, oxygen, hydrogen, and nitrogen
How do plants store excess glucose
Starch
What is carbon hydrate
made up of long chains of sugar that can form starch, glycogen, or cellulose
What is fat and its relation to lipid
made up of 1 glycerol molecule and 3 fatty acid that form oil and fats
Fat is a type of lipid
What is protein and examples
Long chains of amino acids and the seqeuence determine their function
Hemoglobin, pepsin, Amylase
What elements are carbohydrate made up of
carbon, hydrogen, oxygen
Describe the structure of a DNA [3]
1) Double
helix
2) each strand contains chemicals called bases
3) bonds between pairs of bases hold the
strands together
dialysis tubing
Acts as a substitue for smei permeable membrane in experiments for osmosis
Define catalyst
a substance that increases
the rate of a chemical reaction and is not
changed by the reaction
Define enzyme
proteins that are involved
in all metabolic reactions, where they function as
biological catalysts
Why are enzymes important?
Increases rate of reactions necessary for survival
explain enzyme action [4]
1) Substrate binds to the complementary shaped active site of the enzyme where the reaction occurs
2) Enzyme can only bind with certain shapes of substrate and vice versa
3) An enzyme substrate complex is formed after the combine
4) The substrate will leave after the product is formed and the enzyme can bind again
Explain the specificity of enzymes
Each enzymes can only catalyst reactions with correct shape substrate which is complementary to the enzyme
Explain the effect of changes in temperature on enzyme activity[5]
1) The higher the temperature, the more kinetic energy the substrate and enzyme have
2) More collisions so more reactions as subtrate and enzyme bind often
3) Optimum temperature which is when the temperature has highest rate of reactions
4) Gradually the heat causes bonds that hold enzyme to break and lose its shape and become denatured.
5) Substrate can no longer fit into the active site and reaction stops
Explain the effect of changes in pH on
enzyme activity[3]
1) If the pH is too high or low, the bond that hold the chains of amino acids chain together in an enzyme is destroyed
2) causing the active site of the enzyme to change shape and become denatured
3) Optimum pH depends on the enzyme
Denature
enzyme breaks as the bonds are broken and lose its shape, this is irreversible
protease/pepsin/trypsin
enzyme that works in acidic conditions in the stomach is
amylase
Works in saliva
lipase
Fats are broken down by lipase
enzyme-substrate complex
when the substrate binds with the enzyme’s active site
